Do you want to create new calendar recurring event from SharePoint workflow?

You can easily create simple calendar event (which doesn’t have recurring properties/values), some days before I
was trying to create new recurring event from SPD workflow using “Create Item” action, and found that we can’t create recurring event from SPD workflows because when we’re trying to add new calendar list item from ‘Create Item’ OOB workflow action, at that
point we can’t assign the recurring rules values to ‘Recurrence’ column and there is not any available way to pass recurrence rule xml values.

In SharePoint Designer workflow, add your custom activity, assign Name and Recurrence Rule pattern as in XML format. You can check more recurrence patterns from Here.

(NOTE : Rule value must be in single line text, I have used as " <recurrence><rule><firstDayOfWeek>su</firstDayOfWeek><repeat><daily dayFrequency='2' /></repeat><windowEnd>2011-12-30T09:00:00Z</windowEnd></rule></recurrence>
")